The installation of rigid pipe, particularly a cast-iron pipe employed for sewage, sanitary and domestic plumbing requirements, typically requires the coupling or clamping together of the pipe ends in a fluid-tight, sealing, aligned relationship. Some such pipes have complimentary bell and spigot ends, and are joined together easily in the desired sealing relationship, without the absolute requirement for pipe-clamping or -coupling assemblies external to and about the coupling ends of the pipe. Other cast-iron or rigid plastic-type pipes require aligned end-to-end sealing where the ends of the pipe are each identical and are placed in an aligned abutting relationship. Such pipes require an external pipe-coupling or pipe-clamping assembly to secure the end-to-end pipes together in an aligned fluid-tight relationship. Bell- and spigot-type pipes may be assembled easily employing a peripheral-type gasket to insure a fluid-tight relationship, and, although not required, coupling or clamping means may be used also to retain the bell and spigot in the desired position.
Pipe-coupling and pipe-clamping assemblies for end-to-end pipe coupling have been proposed, such as, for example, as set forth in U.S. Pat. No. 3,104,898. This patent describes a tube or pipe-coupling means employing an encircling fixing band having a plurality of fingers extending circumferentially about a pipe joint having flared exterior end surfaces, and a ring-clip means to tighten the band about the abutting pipe joint.
Another pipe joint assembly is described in U.S. Pat. No. 3,233,922, wherein a corrugated-type clamping band is employed, together with an elastomeric inner seal, the corrugated band overlapping at its end and enclosing the elastomeric seal, and having external band-compressing straps. The corrugations on the external overlapping ends of the band make this pipe joint difficult to adjust where there is a variance in the external diameter tolerations of the end-to-end pipes to be joined. Other pipe-coupling means are shown in U.S. Pat. Nos. 3,565,468, 3,211,475 and 2,958,549 as representative of various coupling and clamping means employed in pipes, wherein a compressible band is employed around the pipe joint.
It is, therefore, desirable to provide a simple, easily manufactured and easily applied economical coupling- or clamping-means assembly to join pipes in a fluid-sealing relationship and an end-to-end relationship, particularly pipes which have identical ends. The clamping assembly should provide for the slight variations in the external pipe diameters, particularly with cast-iron pipes employed for domestic plumbing and sewage applications, and also should prevent movement and permit easy placement of encircling-compression straps used in the assembly.